(4) Enhancements to Apple's iOS 8 and OS X Version 10.10 that enable apps to share functions in other apps. See "iOS 8" in iOS versions.

(5) A file type that is appended to the end of a file name. All executable programs in the Windows and Mac worlds use extensions: .EXE in Windows; .APP in Mac (see APP file). In the Unix/Linux environment, "executables" do not use an extension, but no matter which environment, "data" files have extensions. For example, a file with a .DOC or .DOCX extension is a Microsoft Word document. A file with a .JPG extension is a JPEG image.

Prior to Windows 95, extensions were limited to three characters. Starting with Windows 95, they can be very large (254-260 characters depending on Windows version); however, they are kept small in practice.